Dealing with intractable weeds

Research on understanding, inducing and overcoming stress tolerances, developing herbicide resistant crops, especially for the control of parasitic weeds in Africa and around the Mediterranean. The technologies developed with CIMMYT in Africa have been commercialized with herbicide resistant maize using novel seed treatment technologies we developed to lower the amount of herbicide needed, and preclude the need of spraying.  Slow release formulations were developed to preclude crop damage in dry yeas, and to extend the duration of activity of the herbicides, and the research is being followed with collaborators in Germany and Kenya.

Overcoming stress protection responses that preclude efficient biocontrol of weeds: The work needing new manners of controlling weeds led also to the development of transgenic biocontrol agents ("mycoherbicides") to overcome the evolutionary barriers that kept specific pathogens in balance with their hosts. The use of weed-specific pathogens has been touted as a "natural" (i.e. non chemical) way of preventing damage by weeds. The problem is that huge inocula are needed to overcome the natural stress tolerance systems activated by the weeds. We initially developed strategies using chemical synergists to inhibit weed responses to infection and more engineered hypervirulence transgenes into the biocontrol agents.  Biosafety aspects were addressed by developing strategies to prevent organism spread as well as to render the transgenic biocontrol agents unfit to exist in the wild, as well as render any hybrid progeny unfit to exist in the wild.  Research continues by collaborating with researchers abroad in this area.